For many years, it has been customary, when spending a day at the beach, to make use of a large umbrella to provide protection from the sun. Usually, such beach umbrellas are provided with a long staff or stake that can be driven into the sand. This stake is intended to locate the umbrella firmly in place and to permit a determination of the angle at which the umbrella is to be directed.
Unfortunately, even though the umbrella would remain in the selected position in still air, at an ocean beach the wind is usually very strong. The result is that beach umbrellas are often lifted out of the sand and carried away. Not only is this a nuisance, but the danger to other persons on the beach is evident, particularly because of the fact that the umbrella has various sharp protuberances.
Attempts have been made in the past to cure this defect in conventional beach umbrellas in various ways; one of the common suggestions involves providing the umbrella pole with a screw-type extension. For instance, the U.S. Pat. No. to SNOOK #1,736,177 shows a tubular socket for receiving the umbrella pole, which socket is provided with a cast screw at the lower end. The U.S. Pat. No. to JONES #2,103,948 describes a pointed socket for application to the lower end of the umbrella staff, which socket is provided with a helical threads. The U.S. Pat. No. to BEITER #2,209,504 concerns a cast staff tip that is formed with a deep double helix. The U.S. Pat. No. to MERCER #2,211,283 describes an attachment for an umbrella staff that includes a threaded auger-like tip. In the U.S. Pat. No. to WARTH #3,286,962, the staff socket is provided with an open helical skewer, while the U.S. Pat. No. to SHPIGEL et al #4,819,904 shows an attachment for the bottom of an umbrella pole that has a flat helical screw-thread formation, and the U.S. Pat. No. to MORGULIS #4,832,304 shows a ground-anchoring device for umbrellas that has spiral threads.
It is evident that these prior art devices lack several qualities to make them effective, including the fact that their screw threads are, because of the fabrication method used, of small lateral extent. This means that, although they can be buried easily in the sand, they do not grip well enough to resist the strong action of the ocean breeze on the umbrella. In addition, they are clearly expensive and excessively complicated. They are generally effective in aiding in the driving of the stake into the ground, but they lack the ability to hold effectively when buried in a sandy beach. These and other difficulties experienced with the prior art devices have been obviated in a novel manner by the present invention.
It is, therefore, an outstanding object of the invention to provide an anchor device that is very effective in resisting wind forces on an umbrella at the beach.
Another object of this invention is the provision of an anchor device that can be used in converting an ordinary umbrella pole or stake to one which can be useful at an ocean beach.
A further object of the present invention is the provision of an anchor kit for application easily to an umbrella stake.
A still further object of the invention is the provision of an anchor device which is simple and rugged in construction, which can be easily manufactured from readily-available materials, and which is capable of providing a long life of useful service with a minimum of maintenance.
It is a further object of the invention to provide an anchor screw that will operate well in sand, so that it can be used with a beach umbrella to establish the umbrella firmly in place.
Another object of the invention is the provision of an anchor device that can be used on umbrella staffs of various diameters.
With these and other objects in view, as will be apparent to those skilled in the art, the invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.